There is conventionally known a vehicle system including a portable terminal carried by a user of a vehicle and an in-vehicle apparatus mounted on the vehicle to have a communication with the portable terminal. In such a vehicle system, when the portable terminal enters a range within a predetermined distance from the vehicle, the communication is automatically performed between the in-vehicle apparatus and the portable terminal. For example, when the in-vehicle apparatus transmits a request signal to the portable terminal, the portable terminal transmits an answer to the in-vehicle apparatus. There may be cases that a repeater that receives and relays the radio waves from the in-vehicle apparatus. In such cases, even if the portable terminal is located at a position away from the in-vehicle apparatus, the portable terminal would perform communication processing as if the portable terminal is within the predetermined distance from the in-vehicle apparatus (hereinafter referred to as performing an erroneous operation).